1. Field of the Invention
The invention relates to an open-end spinning apparatus with a feed device for supplying sliver, a device for separating the sliver into individual fibers, a fiber guide channel for pneumatically transferring the individual fibers to a spinning rotor, and a lid with a centrally disposed yarn draw-off tube for closing the spinning rotor, an end region of the fiber guide channel extending in the lid extension is constructed in such a way as to be curved in the direction of rotor rotation.
In order to be able to produce open-end yarns of good quality, certain peripheral conditions must be met in terms of the mutual configuration and dimensioning of the spinning elements. For instance, the spinning rotor, the fiber guide channel, the lid closing the spinning rotor, and the yarn draw-off tube must be adapted to one another.
It has been found that the structure of the fiber guide channel, especially, has a considerable influence on the yarn quality which is attainable.
In the past, various attempts have already been made to find an optimal structure of the fiber guide channel. In the process it was found that the structure of the orifice region of such fiber guide channels in particular has a considerable influence on the yarn quality which is attainable.
German Petty Patent GM 78 20 853, for instance, discloses an open-end spinning apparatus having a fiber guide channel which has a substantially rectilinear course. The fiber channel ends at the cylindrical periphery of a lid extension protruding into the spinning rotor. The individual fibers that are combed out by a yarn separating roller in that configuration are fed directly, without any special deflection, onto the fiber slide wall of the spinning rotor and in the process are curved considerably or intermingled by the air stream revolving in the spinning rotor. The fibers can then no longer be adequately straightened out along their relatively short path to the fiber collecting groove of the spinning rotor, and therefore the yarn qualities attainable in such spinning equipment cannot be satisfactory.
German Published, Prosecuted Application DE 21 19 572 describes an open-end spinning apparatus with a fiber guide channel constructed in curved fashion in its end region. The fiber guide channel ends, as usual, in a lid extension protruding into the spinning rotor and has an orifice region that for the most part is open. The inner side wall of the fiber guide channel is constructed in such a way as to be curved in the rotor rotation direction in the orifice region.
A similar spinning apparatus is also known from Published Japanese Application 60-119230. That patent application describes various variants of a possible embodiment of the orifice region of a fiber guide channel. The numerous drawings show orifice regions by way of example in which either the inner or outer external wall is curved in the direction of rotor rotation. Variants are also shown in which both side walls are curved in the rotor rotation directions. The orifice region of the fiber guide channel in that case forms a large outlet opening that widens in delta-like fashion.
Austrian Patent 267 376 also discloses constructing the fiber guide channel as a fiber delivery tube with a streamlined, teardrop-shaped cross section. The part of that yarn delivery tube that curves spirally in the direction of rotor rotation comes to a sharp-pointed end in the end region. Also disposed in that end region of the fiber delivery tube is the fiber outlet opening, which is constructed as a longitudinal slit that comes to a point at the end.
While the transition of the individual fibers emerging from the fiber guide channel onto the slit wall of the spinning rotor is improved through the use of the systems described above, the problem of fiber turbulence in that region is nevertheless not adequately overcome.